638138232 has 96 divisors (see below), whose sum is σ = 1802314800. Its totient is φ = 203793408.

The previous prime is 638138219. The next prime is 638138239. The reversal of 638138232 is 232831836.

638138232 is a `hidden beast` number, since 638 + 13 + 8 + 2 + 3 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638138239) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 162144 + ... + 166032.

Almost surely, 2^638138232 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638138232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (901157400).

638138232 is an abundant number, since it is smaller than the sum of its proper divisors (1164176568).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638138232 is a wasteful number, since it uses less digits than its factorization.

638138232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3997 (or 3990 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 638138232 is about 25261.3980610733. The cubic root of 638138232 is about 860.9374274154.

The spelling of 638138232 in words is "six hundred thirty-eight million, one hundred thirty-eight thousand, two hundred thirty-two".